Introducing the Furman BATT1500-EXT Battery Extension Pack For F1500-UPS and MB1500. This rack-mountable device extends the battery runtime of the MB1500 and F1500-UPS by up to 4 times. It's 2U size matches the UPS's esthetics and can similarly be tower or rack mounted. It's heavy gauge power cord is adapted with DC connectors for easy, plug-and-play install. This metal enclosed battery extension pack houses eight 12V 9Ah batteries that are connected by way of two strings of four in serial.